Mapping Environmental Suitability for Malaria Transmission, Greece

Bertrand Sudre, Massimiliano Rossi, Wim Van Bortel, Kostas Danis, Agoritsa Baka, Nikos Vakalis, and Jan C. Semenza

Author affiliations: European Centre for Disease Prevention and Control, Stockholm, Sweden (B. Sudre, M. Rossi, W. Van Bortel, J.C. Semenza); Hellenic Centre for Disease Control and Prevention. Athens, Greece (K. Danis, A. Baka); National School for Public Health, Athens (N. Vakalis)

Abstract

During 2009–2012, Greece experienced a resurgence of domestic malaria transmission. To help guide malaria response efforts, we used spatial modeling to characterize environmental signatures of areas suitable for transmission. Nonlinear discriminant analysis indicated that sea-level altitude and land-surface temperature parameters are predictive in this regard.

Malaria was eliminated in Greece in 1974 (1,2); however, cases continue to be imported from countries to which malaria is endemic (3) and locally acquired cases have occurred sporadically (4,5). During 2009–2012, health authorities in Greece recorded 267 malaria cases. Although most cases were imported, at least 69 (26%) occurred in patients who did not have travel histories to malaria-endemic regions. A cluster of 6 locally acquired Plamosdium vivax malaria cases occurred during August–October 2009 in the southern Peloponnese (Evrotas Municipality, Lakonia district); in addition, 1 autochthonous case was reported from Marathon Municipality, East Attiki district (2). In 2010, locally transmitted cases were recorded in the same Lakonia district, 1 in East Attiki and 2 in children in central Greece (Viotia district). In 2011, a total of 42 autochthonous cases of P. vivax malaria were reported, representing 44% of the 96 notified cases in 2011. Most (36) of those cases were notified in the Evrotas municipality. In 2012, locally acquired cases appeared to have decreased, with 16 cases representing 21% of the overall number of cases. The ongoing transmission of P. vivax by local anopheline mosquitoes raises concern about reemergence of malaria transmission in Greece in areas that are hospitable to the vector and have permissive environmental and climatic conditions (6).